Despite its macho name, this is not quite as powerful as I had hoped. It seems to be well made and reasonably robust although you obviously have to avoid hitting walls, the ground or other hard objects. It runs from two C batteries (the mid-size cylindrical ones, not so often seen any more, although still widely available) which are supplied so you can get zapping straight away. It is about the size of a squash racket and a little heavier in the handle because of the batteries. It is activated by a push button on the handle which needs holding in - quite an easy action, and a good idea because it means it is automatically off unless the button is depressed. I tried it first on a large black house fly. They are surprisingly agile when pursued around the kitchen, and it is here that you must remember not to hit anything (or anyone) else. The first hit elicited a satisfying crackling noise, but the fly seemed wholly unaffected. A second hit might have slowed it down a little, but it flew out before I could try again. Second was a smaller black house fly which was felled with a single hit - very satisfyingly, it just fell out of the air. So far 1-1. A second small black house fly was felled on the third hit, although after the second it was clearly disorientated.
Weirdly, I just noticed the case (which I think is a cheap squash-racquet case) says on it "When an insect contacts the charged grill, it produces a spark that looks and sounds cool. Touching the grill is uncomfortable for humans yet cannot kill most big flies without repeated zaps" so I guess this says it all.
So far this thing has provided some amusement and exercise, but it you really want to kill things first hit, then a traditional swatter might still be better. My suspicion is that it will be better on smaller flies, and my fear is that it might just annoy wasps, but only time will tell - I will try to remember to update this in a few weeks.
A couple of weeks later...it stuns wasps, sometimes after a couple of hits, but they recover unless you squish them as well. Smaller flies are fried